Inconsitant Animations when uploading to UE4 with the Send to unreal Tool
This may have nothing to do with your problem, but I know Unreal can be very particular about your bone settings, particularly if you have IK bones. If you haven't already, you should go to the Skeleton tab up in the upper right corner and scroll through your Skeleton Tree tab. All the IK bones should be set to 'Animation.' That's the only thing I can think of.